Lathe



Feb. 20, 1945. G, w MZCKEE 2,369,904

LATHE Filed April 26, 1945 e sheets-sheet 2 G. W. MC KEE Feb. 20, 1945.

LATHE Filed April 26, 1943 6 Sheets-Sheet 3 LATHE 'Filed April 26, 1943 6 Sheets-Sheet 4 Feb. 20, 1-945. y G. w. MCKEE LATHE Filed April 26, 1943 6 Sheets-Sheec 5 Feb. 20, 1945. G. w. MQKEE 2,369,904

LATHE Filed A prl 26, 1943 6 Sheets-Sheet 6 y www j Patented Feb. 20, 1945 Zyliddtt LATHE Garnet W. Mclee, Rockford, Ill.; Lulu B. McKee, executrix of said Garnet W. McKee, deceased,

assignor to herself Application April 26, 1943, Serial No. 484,550

36 Claims.

The present invention relates generally to lathes. More particularly the invention relates to that type of lathe which is designed to provide a. metallic part, such asa cock plug; with a smooth external surface of circular cross section and as its primary parts comprisesil) ahorizontally elongated supporting structure, (2) an electric motor ywhich is mounted on one end of the supporting structurein such manner that the amature shaft thereof extends lengthwise or longitudinally of the structure, and has on the inner end of its armature shaft a chuck for supporting the large end of the plug and effecting drive or rotation of the plug in response to operation of the motor, (3) an axially slidable centering pin which is positioned in opposed relation with the'chuck and is adapted when shifted towards the chuck after application of the large y end of the cock plug to the chuck to engage and support the small end of the plug, and (4) a plunger which is located at one side of the centering pin, has the end thereof that is remote from the chuck slidably mounted in a cylinder on the other end of the supporting structure, embodies at its other or exposed end a laterally extending cutting tool, and is adapted when fluid under pressure is introduced into the cylinder to slide in the direction of the motor and cause the cutting edge of the tool to traverse the plug and provide the desired external surface thereon.

One object of the invention is to provide a lathe of this type which is an improvement upon, and has certain inherent advantages over, previously designed lathes and is characterized by extremely high efficiency and speed of operation.

Another object of the invention is to provide in connection with a lathe of the type and character under consideration novel -means or mechanism for automatically controlling the electric motor, the centering pin, and the tool carrying plunger.

Another object of the invention is to provide a lathe of the aforementioned type in which the control means for the centering pin operates directly after the'tool equipped plunger completes its stroke to effect shift of the centering pin into its plug releasing position to the end that the y plug moves by gravity out of place and hence is a latheof the type under consideration in which the electric motor is laterally adjustable with respect to the supporting structure in order that the chuck maybe shifted in a sidewise manner with respect to the centering pin for purposes of varying the amount of taper that is formed by the cutting tool on the plug during the cutting stroke of the plunger.

Another' object of the invention is the provision of means for jetting air under pressure against the tip or point of the centering pin when it is in its retracted or plug releasing position in order to clean the tip or point of any cuttings or other foreign particles which would preclude the pin from functioning properly when next shifted into its plug supporting position.'

A further object of the invention is to provide in connection with a lathe of the type under consideration novel means for lubricating the piston and cylinder and the parts that are associated therewith.

A still further object of the invention is to provide a lathe whichv is generally of new and improved construction and not-only involves a novel arrangement of parts but also is capable of being produced and operated at an extremely low cost. l

Other objects of the invention and the various advantages and characteristics of the present lathe will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in which like letters and numerals of reference de/` note corresponding parts throughout the several views:

Figure 1 vis a side View of a lathe embodying the invention, parts of the supporting structure being broken away in order to show the arrangement and design of the motor driven pump for supplying iiuid under pressure into the cylinder in order to produce the cutting stroke of the tool carrying plunger; f v

Figure 2 is a plan view ofthe lathe;

Figure 3 is an enlarged vertical longitudinal section taken on 'the line 3-3 of Figure 2 and illustrating in detail the mounting for the axially slidable centering pin;

Figure 4 is a horizontal section taken on the line li--li of Figure 3 and showing in detail the arrangement and design of the block and guide bar for controlling the plunger so that it moves truly rectilinearly in connection with its cutting stroke regardless of any looseness between the plunger and the cylinder;

Figure 5 is an enlarged vertical transverse section on the line 8-8 of Figure 1;

Figure 6 is an enlarged vertical transverse section on the line 8-8 of Figure 1;

Figure 1 is an enlarged vertical longitudinal section taken on the line 1-1 of Figure 2 and illustrating in detail the construction and design of the piston and cylinder and the means for lubricating the latter and the parts that are associated therewith;

Figure 8 is an enlarged vertical transverse section taken on the line 8-8 of Figure 7 and showing in detail the construction and design of the valve for retarding the tool carrying plunger during the initial part of its retractile stroke;

Figures 9 and 10 'are perspectives of the side plates of the plunger retarding valve; and

Figure 1l is a diagrammatic view of the automatic control means for the electricmotor, centering pin and plunger.

The lathe which is shown in the drawings constitutes the preferred form or embodiment of the invention. It has many capabilities of use although it has special utility in providing a tapered cock plug p with a truly conical or tapered external surface. As shown in the drawings, the plug p is of conventional or standard construction and has a cross port in the central portion thereof, a polygonal handle receiving lug at its large end and a reduced externally threaded nut receiving stem at its small end. As its main or primary parts the lathe comprises a supporting structure I2, a three-phase electric motor I3, a centering pin I4, a plunger I8, and automatic control means for the motor, centering pin and plunger.

Supporting structure The supporting structure I 2 serves as a medium for holding the various operating parts of the lathe in an elevated position with respect to the floor of the room or space in which the lathe is used and embodies an elongated, horizontally extending, hollow, cylindrical, open ended frame member I8. This member is supported in an elevated position by way of a plurality of depending legs I1 and carries on the upper portion the cap screws 23 are loosened. An upstanding rib 24 is suitably ilxedly connected to the upper face of the web of the channel beam I8 and is disposed beneath the central portion of the motor I3. This rib fits within a transverse groove 28 in the bottom face of the bed plate 2| and coacts with the groove to form a sliding connection whereby the bed plate and electric motor are conned to truly rectilinear movement in connection with lateral adjustment thereof. As hereinafter described, lateral adjustment of the bed plate and motor in one direction serves to decrease the amount of taper of the plug p and laterally adjustment of the bed plate and motor in the opposite direction serves to increase the amount of taper oi' the plug. A micrometer type adjusting device 28 is associated with the electric motor I3 and serves to adjust or shift the latter laterally upon loosening of the cap screws 23. This device, as shown in Figure 2, comprises a bolt 21 which projects outwards from one side of the motor casing I8. 'I'he head'oi' the bolt is thereof a channel beam I8. The latter extends Electric motor and associated parts The electric motor I3 is positioned over one end of the channel beam I8 of the supporting l structure I2 and comprises a casing I8 and an armature shaft 28. armature shaft 20 thereof extends lengthwise of the supporting structure and is mounted on a bed plate 2i. The casing of the motor is flxedly secured to the bed plate by way of cap screws 22. The bed plate tits ilatly against the upper face of the web of the channel beam I8 and is adjustably secured in place by means of cap screws 23 which extend through horizontally elongated holes 24 in the bed plate. The holes are elon- It is arranged so that the gated in a transverse direction relatively to the supporting structure and 'permit the bed plate and electric motor to be adjusted laterally when disposed adjacent the motor casing and is maintained in fixed relation with the casing by way of a bracket 28 which is bolted to the bed plate 2|. The outer end of the shank of the bolt 21 extends loosely through a. sleeve 28 and is provided at its extremity with a nut 30 which engages the outer end of the sleeve. The inner end of the sleeve embodies an external screw thread of extremely small pitch and extends through an internally threaded bore or opening in a bracket 3l on the web of the channel beam I8. A compression spring 32 surrounds the central portion of the shank of the bolt 21 and is interposed between the brackets 28 and 3i. If, after loosening of the cap screws 23, the sleeve 29 is turned so that it is caused `to feed or move axially away from the bracket 28 it shifts the bolt 21 in such direction as to cause the bed plate and motor to move towards the fixed bracket 3i on the web of the channel beam I8. When the sleeve 29 is reversely rotated after loosening of the cap screws 23 it feeds inwards relatively to the bracket 3i with the result' that the compression spring 32 operates to, shift the bed plate and motor away from the bracket 3| a distance corresponding to the amount of inward feed of the sleeve 29. When the bed plate and motor are adjusted into the desired position by turning of the sleeve 29 the cap screws 23 are tightened so as to lock the bed plate and motor in place. An arm 33 is connected to, and extends radially from, the outei end of the sleeve 28 and serves as a medium for turning the sleeve for bed plate and motor adjusting purposes.

The inner end of the armature shaft 20 of the electric motor I3 projects outwards of the motor casing I9 and is provided with a chuck 34 for supporting the large end ofthe plug p and eiecting drive or rotation of the plug in response to operation of the motor. 'I'his chuck (see Figure 3) is provided with a. central polygonal slot 35 for receiving the polygonal lug on the large end oi the plug and embodies a centering pin 38. The latter is in axial alignment with the armature shaft of the motor I3 and has a tapered or pointed end which faces the slot 38 in the chuck and is adapted to llt within a tapered socket in the central portion of the polygonal lug on the plug p. In connection with a surface cutting operation the lug on the large end of the plug is inserted into the slot 35 in the chuck and the plug is adjusted laterally until the pointed end of the centering pin 38 fits within the aforementioned tapered socket. When the point is in the socket the large end of the plug is properly centered with respect to the axis of the armature shaft andthe chuck is in driving relation with the lug on the large end of the plug and serves to effect drive or rotation of the Aplug in response to operation of the electric motor. The slot 35 in the chuck is c of slightly larger size than the polygonal lug on the large end of the plug in order to permitthe lug to be quickly inserted into, and removed from, the slot. g f

The outer end of the armature shaft ZII .projects beyond the adjacent end of the motor casing I9 and has applied to it a solenoid type brake 31 for stopping the armature immediately upon interruption of the flow of current to the motor. The brake is of standard or conventional construction and comprises an upstanding brake shoe 39' and a solenoid 39. The shoe is hinged at its lower end sol that it is free to swing to and from the outer end of the armature shaft. A compression spring'40 is'applied to the upper end of the brake shoe and serves 'to urge the: shoe intobraking relation with-said outer end ofthe armature shaft. The solenoidv 39 comprises a vertically movable armature (not shown) and this inconnected to the upper end of the brake shoe by way of a lever varrangement which is so designed or arranged that when the solenoid is energized it forces the brake shoe away from the outer end of the armature shaft against the pressure or force of the compression spring 40. When the solenoid 33V is de-energized the compression spring 40 swings the brake shoe 38 into gripping or braking relation with the outer end of the armature shaft.

The electric motor I3 is automatically controlled as hereinafter described and the solenoid 39 of the solenoid brake 31 is in circuit with the motor circuit. f

centering pin and associated parts The centering pin I4 serves as a medium for c type upper section 43. The lower'section 42`is bolted or otherwise i'lxedly secured to the end of the web of the channel beam that is remote from the electric motor I3. It comprises a bottom wall, a pair of side walls, an inner end wall and an outer end wall and underlies andsupports the upper housing section 43. In addition to the aforementioned walls thelower section 42 embodies a transversely extending, upstanding partition 44 and this is disposed slightly inwards ci' the inner end wall and divides the. interior of the lower section 42 into a small sized inner cham ber 43 and a large sized outer chamber 46. The cross partition 44 is imperforate with'the result that the two chambers do not communicate with one another. The upper section 43 of the housing 4I is xedly secured to the lower section 42 in any suitable manner and is the same in shape.

The bottom face of the upper section extends,

aci-oss the upper edges of the lvarious walls and the cross partition of the lower section and serves to cover the chambers 45 and 46. The inner chamber 45 is partly filled with oil and the latter serves, as hereinafter described, to actuate the centering pin I4. Ihe outer chamber 46 is partially filled with oil and is vented by way of a vent hole 41 in the upper portion of the outer end wall of the lower section 42 of the housing di. The inner end of the centering pin ld, that is, the end that is farther or remote from the chuck ed, is provided with an enlarged head 43 and is disposed in a cylindrical socket 49 in the inner end portion of the upper section da of the housing di. The central and outer end portions of the centering pin are slidably mounted in a tubular member 50, the inner end of which is provided with a radially extending flange 5I in abutment with the inner end face of the upper housing section d3.

l Cap screws 52 extend through the ilange and the adjacent portion of the upper housing section 43 and serve tohold the tubular member 5d in connected relation with said upper housing section. The outer end portion of the centering pin I4 is Provided with a point 53 which when the centering pin is shifted'towards the chuck, is adapted to t within a tapered or conical socket in the externally threaded reduced stem on the small end of the plug p and serves when in the socket to support said small end ofthe plug. The

centering pin is retracted or shifted inwards into a plug releasing position by way of a compression spring 54. The latter surrounds the inner end of the centering pin and has one end thereof in abutment with the enlarged head d5 and its other end in abutment with a shoulder 55 in the central portion of the tubular member 50. The enlarged head B8 coacts with the inner portion of the annular flange 5I to limit sliding movement of the centering pin I4 in the direction of the chuck 3d. A vertically extending duct 56 (see Figure 6) is formed in thehousing di and establishes communication between the bottom portion of the chamber d5 `and the bottom portion of the socket S9. Air under pressure is supplied to the upper portion of the chamber t5 by way of a horizontally extending pipe 51 and a vertical pipe 58. The horizontally extending pipe 5l extends lengthwise of that portion of the space between the channel beam I8 and the upper portion of the tubular member that underlies the housing di. The

outer end of the pipe 57 is connected to one of the end branches of a JT iltting 59. The central branch of this T iitting is provided with a coupling 80 for connection to any suitable source of air under pressure. The other end-branch of the T fitting is connectedto one end of an exhaust pipe 6I and such pipe. as shown in Figure 7, has a solenoid valve 62 associated with it. The vertical pipe 53 is disposed in the chamber d5 in the inner portion of the lower section d2 in the housn ing 4Ik and is arranged so that the upper end thereof terminates adjacent the upper portion of the chamber at a point above the level of the oil in the chamber. The lower end of the pipe 55 extends through a sealed hole in the bottom wall of the lower housing section 42 and is connected to the inner end of the horizontallyextending pipe 5l by an elbow 63. As shown Idiagi-ammatically inFigure 11, the solenoid valve 52 in the exhaust pipe 6I comprises'a casing ed having in the in terior thereof -a partition 55 with a valve seat ed therein. It also comprises a vertically movable valve member 51 which is urged downwards into seated relation with the seat either by gravity or the solenoid part of the valve is de-energized the armature 69 moves downwards and effects closing of the valve member 61. When the solenoid valve 62 is closed as the result of the solenoid part being energized air under pressure flows through the pipes 51 and 58 into the upper portion of the chamber 45 and creates such pressure that the oil in the chamber is forced upwards through the duct 56 into the socket 49. The oil that enters the socket as the result of closing of the solenoid valve 62 forces the centering pin I4 so that it slides towards the chuck 35 into its plug supporting position. When the solenoid valve 62 is opened the pressure within the upper portion of the chamber 45 is dissipated with the result that the oil in the socket 49 ows back into the chamber 45 and releases the centering pin I4 so that it is retracted by the action of the compression spring 54. From the foregoing it is manifest that when the solenoid valve 62 is closed the centering pin I4 moves into its operative or plug supporting position and when the solenoid valve 62 is opened the centering pin I4 is shifted rearwards into its retracted position by the spring 54. The upper end of the vertical pipe 58 is surrounded by a cup shaped baille so as to prevent oil in the chamber 45 from entering the pipe 58 when the pressure within -the chamber is released as a Aresult of the opening of the solenoid valve 62. The discharge end of the exhaust pipe 8| is arranged so that it extends along one side of the housing 4I and is provided at its extremity with a nozzle 1I. This nozzle is carried by a bracket 12 on the tubular member 50 that serves slidably to support the centering pin I4. It is directed downwards towards the point 53 of the centering pin and serves, when the solenoid valve 62 is opened for the purpose of effecting shift of the centering pin I4 into its retracted or plug releasing position, to jet air downwards onto said point 53. The jet of air that emanates from the nozzle 1I in connection with opening of the solenoid valve 62 operates to clean the point 53 of any cuttings or other foreign particles which would preclude the pin from functioning properly when next shifted into its plug supporting position. When the solenoid is closed in order to eiTect shift of the centering pin I4 into its plug supporting position no air emanates from the nozzle 10. However, air does emanate from the nozzle for point cleaning purposes immediately upon opening of the solenoid valve 62. The bracket 12 embodies a depending member 13 which underlies the outer end of the tubular member 50 and carries an upstanding plate 14. The upper portion of 4this plate is provided with a V-shaped notch 'I5 which is adapted to receive the reduced, externally threaded stem on the small end of the cock plug p before shift of the centering pin I4 into its plug supporting position, and also to receive the exy ternally threaded stern on the small end of the plug immediately upon retraction of the centering pin into its plug releasing position. The notch 15 is located beneath and to one side of the point 53 of the centering pin I4 with the result that when the reduced externally threaded stem on the small end of the plug is disposed therein the .stem is not truly aligned with the point 53 of the centering pin I4 and the plug is in a non-cutting position. When the centering pin'I4 is shifted towards the chuck into its plug supporting position the point 53 enters the conical socket in the stern on the small end of the plug and, due to the resultant cam action, raises and shifts laterally the small end of the plug until the plug is in tion of the plate 14. As soon as the stem engages the notch the small end of the plug is shifted laterally because of the arrangement or position of the notch 15. In connection with a plug cutting operation the operator of the lathe inserts the polygonal lug on the large end of the plug into the slot 35 in the chuck 34 and then releases the plug. Upon release of the' plug the small end moves downwards and laterally. As soon as the centering pin I4 is shifted toward the chuck 34 preparatory to a cutting operation the point 53, as previously pointed out, enters the conical socket in the threaded stem of the plug and shifts the plug upwards and laterally into its plug cutting position. As soon as the centering pin I4 is released after cutting of the plug the small end of the plug moves downwards and sidewise into a noncutting position and hence-is not subjected to scratching or marring during the retractile stroke of the plunger I5.

Plunger and associated parts The plunger I5 is located at one side of the centering pin I4 as shown in Figures 4, 5 and 6. The notch 15 in the upper portion of the plate 14 is positioned at one side of the centering pin and the plunger is disposed at the other side of the pin. The end of the plunger that is remote from the chuck 34 is slidably mounted in a cylinder 15 in the upper section 43 of the housing 4I in order that the plunger as a whole is slidable towards and away from the chuck. The cylinder 16 extends through both end faces of the upper housing section 43 and has the rear end thereof, that is, the end that is remote from the electric motor, closed by a tubular member 11 and a cupshaped member 18. The tubular member 11 has at the inner end thereof an annular flange 19 and this ts or abuts against the outer end face of the upper housing section 43. Cap screws extend through the flange 19 and into the upper housing section 43 and serve removably to secure in place the tubular member 11. 'I'he interior of said tubular member is aligned with, and of slightly greater diameter than, the cylinder 16 (see Figure '1). A cross wall 8| extends across the central portion of the interior of the tubular member 11 and embodies a central hole 82. TheA cupy shaped member 18 is axially aligned with, and disposed outwards of, the tubular member 11 and comprises a cylindrical or annular side wall and a cross wall. The cross wall is connected to, and extends across, the outer end of the side wall and the inner margin of the side wall extends into the outer end of the tubular member 11 and is removably secured'inplace by a screw thread connection 83. 'I'he members 11 and 18 constitute parts of the housing 4|. The inner end of the plunger I5 is provided with a centrally disposed longitudinally extending stem 84 and this extends loosely through the hole 83 in the cross wall 8l of the tubular member 11 and projects into the interiors of the members 11 and 18. The plunger I5 is retracted, that is, slid or shifted away from the electric motor I3, by Way of a compression spring 85 which surrounds the stem 84. The

inner end of the compression spring abuts against zontally.

by means of ay nut 81. A horizontally elongated block 88 is xedly secured to the outer end of the. plunger'l5 by way of screws 89. 'I'liis blockv projects laterally in Iboth. L directions from the outer or exposed end of the plunger and has in the central portion thereof a horizontal groove 90. 'I'liis groove extends transversely of the plunger and serves as a seat for a cutting tool 9|. The latter is removably held in place by a set screw 92 and has on the end thereof that is near the centering pin I4 a cutting edge 93. When the plunger is shifted towards the electric motor |3 the cutting tool'9| traverses the plug p and the cutting edge of the tool cuts the desired external side surface on. the plug. 'Ihe cylinder 16 `for the inner end of the plunger extends hori- It is, however, positioned at a small acute angle Wtli respect tothe axis of the centering pin I4 with the result that during the cutsurface on the plug. If a gra-dual tapered surface is desired' on the plug the bed plate 2| and the electric motor I3v are adjusted laterally towards the axis of the plunger and this is accomplished by loosening the cap screws 23 and manilpulating the sleeve 29 so that it feeds or moves axially away from the bracket 28. If it is de-` sired to increase the taper of the surface which is formed on the plug by the cutting edge of the tool in connection with shift of the plunger toward the electric motor, the bed plate and electric motor are adjusted laterally in the opposite direction, i. e., away from the axis of the plunger.

A hopper 94 underlies the chuck 34 and the tubular member 50 and serves to catch and direct downwards the cuttings resulting from the action of the tool 92 during shift of the plunger I5V toward the electric motor I3. 'I'he lower end of this hopper extends through aligned holes lilik in the web of the channel beam |8 and the upper portion of the frame member I6 and serves to direct the cuttings into the interior of the frame member. The cuttings which accumulate in the bottom of the frame member vmay be removed from either end of said frame member.

As hereinafter described, current is supplied to the electric motor I3 during the cutting stroke of the tool carrying plunger I5 so as to effect rotation of the plug as the cutting edge 93 traverses the side of the plug. When the plunger reaches the end of its cutting stroke the supply of current to the motor automatically ceases. The plunger is shifted towards the electric motor for plug cutting purposes by introducing oil under pressure into the interiorsof the tubular member 11 and the cup shaped member 18. A gear pump 96 serves as the medium for supplying oil under pressure into the interiors of the members 11 and 18 and this pump, as shown in Figure 1, is suspended from the outer end of the bed plate 2|' by way of a bracket 91. Such bracket extends through cutouts in the web of the channel -beam I8 and the upper portion of the frame member I 6 and connects the pump to the bed plate. so that it is adjustable therewith. The pump 96 is driven from theelectric motor |3'by way of a'pulley and belt connection 98. The latter comprises apulley 99Y on the outer end of the armature shaft 20 of the velectric motor |3, a pulley |00 on one end of the drive shaft of the gear pump 96 and an end llo `ting stroke of the plunger the cutting edge of the tool forms a conical or tapered external side y The pipe |02 extends through the space between the channel vbeam I8 and the upper portion of the frame member I6 (see Figure 1) and is suiiilciently flexible to permit the pump to move with v One end ofk the pipe section |05 is connected to the upper portion oi' the tubular member 11 by a fitting Il and the other end of the pipe section |05 is connected to a retarding valve ||2 by a fitting |13. The pipe section '|06 of the return pipe |04 leads from the retarding valve ||2 to a solenoid valve I|4. The` pipe sectionv |01 leads from the-solenoid valve |`|4 to the central branch of the T'tting |08. The pipe section |09 leads from one end branch of the T fitting |08 to the inlet in the casing of the gear pump 96. The

I branch pipe |I'0 or the return pipe |04 leads from the other end branch of the T fitting |08 through a hole H5 in the outer end wai1 of thelower housing section 42 into the bottom portion of the chamber 46. The inlet end 0I'A the pipe section |06 is connected to the retarding valvev ||2 by a l fitting H6. The solenoid valve ||4 comprises a casing Ill having an inlet |I8 at oneend and an outlet ||9 at its other end. The interior of the casing I|1 is divided by way oi' apartitioh |20 and this is provided with an annular valve seat |2|. The solenoid valve ||4 also comprises a. vertically movable valve member |22 which is urged downwards into seated relation with the valve seat |2| either by kgravity or a spring. The solenoid part of the solenoid valve ||4 vlocated above the casing II'l and comprises a coil |23 and a vertically movable armature |24. The valve member |22 is applied to the lower end of'the armature. When' the solenoid part of the solenoid valve ||4 is energized the armature |24 is retracted and sinfts the valve member |22 up wards into its open position. When the solenoid part of the solenoid valve ||4 is de-energized the armature |24 moves downwards and eii'ects closing of the valve member |22. As hereinafter described, the solenoid part of `the solenoid valve I4 is de-energizeol wi'iile the electric motor |3 is in operation and is energized when the electric motor is not in operation.. In other words, when the motor is in operation the. solenoid valve ||4 is closed and when ther electric motor is not in operation the solenoid valve 4 is open. When the motor is in operation it serves to drive the gear pump 96 and the latter serves to supply oil under pressure into the interiors of the members 11 and 18. Because the solenoid valve ||4 lis closed when the electric motor |3 is in operation the oil under pressure in thev interiors of the members 11 'and 18 builds up and causes the tool carrying plunger I5 to slide towards the electric motor I3 `and effect cutting or surfacing of the cock plug p. When the electric motor |`3 is caused, as hereinafter described, to stop at the end of a cutting stroke of the plunger the pump 98 stops and the solenoid valve ||4 opens. As

soon as the solenoid valve opens the interiors o! the member 11 and 18 are vented with the result that the tool carrying plunger I5 is retracted by the action of the compression spring 86: During the retractile stroke of the plunger the oil in the interiors of the members 11 and 16 is forced through the pipe section |05I the retarding valve II2, the pipe section |06, the casing ||1 of the solenoid valve II4, the pipe section |01, and the branch pipe I I into the chamber 46 in the lower housing section 42. The discharge end of the pipe section |06 ist/connected to the inlet ||8 of the casing ||1 of the solenoid valve ||4. The inlet end of the pipe section |01 is connected to the outlet ||9 of the casing ||1. lI'he portion or end of the branch lpipe I I0 that is disposed in the chamber 46 extends horizontally, as shown in Figure 7, and is located adjacent the bottom of the chamber 46. It has side holes therein for establishing communication between its interior and the body of oil in the chamber 46. When the gear pump 36 is driven as the result of the supply of current to the electric motor I3 the solenoid valve |I4 is closed, as previously pointed out. As soon as the gear pump is set into operation it draws oil from the chamber 46 by way of the branch pipe |'I0 and the pipe section |09 and forces the oil under pressure through the pipe |02 into the interiors of the members 11 and 18 where the oil builds up pressure and forces the tool carrying plunger I towards the motor forvplug surfacing purposes.

As described hereafter, the coil |23 of the solenoid partof the solenoid valve I|4 and the coil 68 of the solenoid part of the solenoid valve 62 are in circuit. As a result of this the two valves open and close simultaneously. Also, as hereinafter described, the two valves are closed when the lathe is started in connection with a plug cutting or. surfacing operation and are opened as soon as the plunger I5 reaches the end of its cutting stroke. The retarding valve ||2 operates to retard the tool carrying plunger II5 during the initial part of its retractile stroke in order to provide ample or suicient time for the centering pin I4 to retract. As thev result of the delaying action of the valve ||2 the plug, after cutting or surfacing thereof, is releasedand drops out of its cutting position before retraction of the plunger and hence there is no likelihood of the cutting edge 93 of the tool 9| marring or scratching the cut tapered side surface of the plug during retraction of the plunger. The valve ||2 is mounted on the outer end portion of the top face of the upper housing section 43 and comprises a box-like casing |25 and a spool type valve member |26. The casing |25 overlies the end of the cylinder 16 that communicates with the inner end of the interior of the tubular member 11 and consists of a rectangular inner block |21 and a pair of side plates |28 and |29. The inner block and side plates extend lengthwise of the cylinder and plunger and are suitably secured together. The inner plug |21 has a horizontal, longitudinally extending inlet duct |30 in its central portion, a horizontal, longitudinally extending bore |3| in its upper portion and a. horizontal, longitudinally extending outlet duct |32 in its lower portion. One end of the inlet duct |30 terminates adjacent the central portion of the inner block |21 of the valve casing |25 and the other end leads through the rear end face of said inner block. The tting |I3 at the discharge end of the pipe section |05 of the return pipe |04 isconnected to said other end of the inlet duct |30. The inner end of the inlet duct |30, that is, the end that terminates adjacent the central portion of the inner block |21, is provided with a laterally extending outlet port |33 and this leads to and through the side face of the block that is engaged bythe side plate |28. The bore I3I extends through both end faces of the inner block |21 of the valve casing |25 and serves slidably to support the spool type valve member |26. An inlet port |34 is formed in the inner block |21 and leads from the side face of the block that is engaged by the side plate |28 to the central portion of the bore |3I. An outlet port |35 is formed in the upper portion of the inner .block |21 of the valve casing |25 and this is aligned with the inlet port |34 and leads to and through the side face of the block that is engaged by the side plate |29 (see Figure 8). 'A vertically extending passage |36 is formed in the inner portion of the side plate |28 of the valve casing I 25 and serves to establish communication between the outlet port |33 and the inlet port |34. The outlet duct |32 is disposed in the inner block |21 directly beneath the inlet duct |30. One end of the outlet duct |32 terminates adjacent the central portion of the block |21 and the other end leads through the rear end face of the block as shown in Figure 7. 'I'he tting II5 at the inlet end of the pipe section |06 of the return pipe |04 is connected to said other end of the outlet duct |32. An inlet port |31 yleads laterally from the inner end of the outlet duct |32, that is, the end that terminates adjacent the central portion of the block |21, to and through the side face of the block that is engaged-.by the side face |29. A vertically extending passage |38 is formed in the inner face portion of the side plate |29 and establishes communication between the outlet port |35 and the inlet port |31. The spool type valve member |26 is provided with an annular groove |39 and is adapted normally to assume an open position wherein the groove |39 is in registry with, and establishes communication between, the inlet port |34 and the outlet port |35.

It is further adapted when shifted in the direc` tion of the electric motor I3, as hereinafter described, to assume a closed position wherein the groove |39 is out of registry with the ports |34 and |35. The rear end of the spool type valve member |26, that is, the end that is farther from the electric motor I3, projects outwards of the valve casing |25 and is provided at its extremity with an enlarged head |40. A compression spring |4| surrounds the rear projecting end of the valve member |26 and serves to urge the valve member into its open position. One end of the spring |4| abuts against the rear end face of the inner block |21 of the valve casing |25 and the other end abuts against the enlarged head |40. A stop nut |42 on the front end of the spool type valve member |26 limits rearward sliding movement of the valve member beyond its open position. The spring |4|, as previously pointed out,normally maintains the valve member |26 inits open position. When the valve member is in its open position while the solenoid valve ||4 is in its open position oil is permitted to flow through the retarding valve ||2 as follows: inlet duct |30, outlet port |33, passage |36, inlet port |34, lgroove |39, outlet port |35, passage |38, inlet port |31 and outlet duct |32. A bleed or by-pass port |43 is formed in the side plate |28 and leads downwards from the bottom portion of the passage |36 to a passage |44. The latter leads to, and communicates with, the inner end of the outlet duct |32. When, as hereinafter described,V the spool type valve member |28 is shifted forwards into its closed position at the conclusion of the cutting stroke of the tool carrying plunger I there is a restricted flow of oil from the inlet duct |30 to the outlet duct |32. Such restricted 'flow results in the plunger moving Irearwards` extremely slowly. The front end of thev spool type valve member |26 is provided witha forwardly extendingrod |45. This rod is in axial alignment with the valve member |26 and provided at its forward or free lend with an enlarged head |46 which coacts with a slide block |41 to effect shift of the spool type valve member |26 into its closed position at the end of the cutting stroke of the tool carrying plunger I5.` The slide block |41 is of two-piece design and comprises a rectangular -bottom part |48 and -a top part |49. The bottom part engages and is supported by the top face of the upper housing section 43 and is mounted in a horizontal rectangular frame |50 so that it is free to slide back and forth lengthwise of the cylinder 16. 'I he frame |50 overlies and extends lengthwise of the cylinder. It is fixedly connected in any suitable manner to the top face of the upper housing section 43 and coacts with the slide block |41 to prevent turning or rotation of the plunger. The top part |49 of the slide block |4`| is rigidly connected to the bottom part |48 and has formed therein a hori zontal hole |5| through which the rod |45 extends loosely. The .slide :block |41 is connected for conjoint sliding movement with the plunger I5 by way of a vertically extending pin" |52. The lower end of this pin is tapered and is driven intov a tapered cross hole |53 in the central portion of the plunger I5. The upper end of the pin extends through a longitudinal slot |54 in the portion of the upper housing section 43 that overlies the cylinder 16, and is provided with a cylindrical head |55. The latter fits within a socket |56 inthe bottom part |48 of the slide block |41. As shown in Figure 2, the slot |54 is of less width than the elongated space within the frame |50. The slide block |41 is so arranged or positioned that the top part |49 thereof strikes against the enlarged head |46 on the front end of the rod |45 as the tool carrying plunger I5 approachesvthe end of its cutting stroke. As the plunger reaches the end of its cutting stroke the stop part |49 of the slide block shifts the spool type valve member |46 of the retarding valve I I2 into its closed position against the force of the compression spring I4 I. During the initial portion of the retractile stroke of the plunger the slide 'block |41 moves towards the casing |25 of the valve ||2 and the spring |4| serves to shift or slide'the spool type valve member |26 into its open position. As soon as the valve member |28 reaches its open .position as the result vof abutment of the stop nut |42 with the front end face of the inner -block |21 of the casing |25 of the retarding valve the slide block |41, in connection with completion of the retractile stroke of the plunger, slides rearwards relatively to the rod |45. As hereinafter pointed out, the solenoid valves 62 and ||4 are opened and the electric motor I3 is stopped 1 when the tool carrying plunger I5 reaches the end ofits cutting stroke.

As soon as the solenoid valvejZ opens the. centering pin I4 is retracted by the compression spring 54. As soon as the solenoid valve ||4 is opened the oil in the members 11 and 18 is perof the compression spring 8B. During the initial part of the retractile movement of the plunger the spool type valve member |26 ofthe retarding valve ||2 is lneits closed position. However, while the valve member is in such position oil is perm-Itted to flow from the inlet duct |30 into the outlet duct |32 through the vbleed or lay-pass port |43. The flow of oil through this port is restricted with the result 'that the initial part of the retractile stroke of the pluer is retarded. As soon as the valve mem-ber |26 of the retarding valve ||2 is shifted into its open position after the initial part of the retractile stroke of the plunger there is a free flow of oil through the retarding valve and the plunger is hence permitted to slide quickly away from the chuck 34. The valve ||2 serves merely as a medium for causing the plunger to move slowly, that is, in a retarded manner during the initial part of its retractile stroke. During the retarded initial part of the lretractile stroke of the plunger the centering pin is retracted by its compression spring y54 and releases the plug p with the result that the plug drops bygravity out of its cutting position and hence is not subjected to scratching or marring by the cutting edge 93 of the tool 9| as the cutting edge lpasses by the plug in connection with completion of the retractile strokeof the plunger.

In order to cause the tool carrying plunger I5 in connection with its cutting stroke to move truly rectilinearly regardless of any looseness -between the plunger and its cylinder 16 a guide bar |51 is provided. This bar is disposed'J in a horizontal position and extends longitudinally of y the supporting structurel I2. It is disposed adjacent that side of the housing 4| that is opposite the centering pin I4. The inner side face of the guide bar |51 is lapped so that it is flat throughout. 'The rear or'outer end of the guide bar ts flatly against the adjacent side face of the upper housing section 43 and is secured in place :by way ofa pair of U-shaped brackets |58. Said adjacent side face of the upper housing section 43 is also lapped and is disposed in parallel relation with the axis of the cylinder 16. lThe free ends of the legs of the brackets |58 are bolted or other- Wise xedly secured to saidA upper housing section 43 and are arranged in straddled relation with the rear end of the guide bar |51. Screws |58 extend through the central portions of the cross parts of the Ibrackets |58 and serve to clamp the rear end of the guide bar in place. The inner or front end of the guide `bar |51 projects beyond the housing 4|, as shown in Figure 2. The tool carrying block 88 is provided with an extension |60 and this has a lapped outer end face which engages slidably the inner or front portion of the inner side face of the guide bar |51. During reciprocation of the plunger I5 the extension slides on the inner end of the guide bar |51 and coacts therewith to cause the plunger to move truly rectilinearly regardless of any looseness betw-een the plunger and the cylinder 16.

The extension |60 and the cutting tool 9| project horipin |52, a vertically extending longitudinal passage |63 in the pin, a cross port |64 at the upper end of the passage |63, an annular groove |65 in the socket defining portion of the bottom part |48 of the slide block |41, and a pair of diametrically opposite, horizontal ports |66 in the side portions of said bottom part |48. The duct |6| extends throughout the full length ofthe plunger and the stem 84, as shown in Figure '1. The rear end of the duct is open with the result that when oil under pressure is pumped into/the interiors of the members 11 and 1.8y by the gear pump 98 a. portion of the oil flows into and through the duct |6I. The annular groove |62 in the central portion of the pin |52 is in registry and communication with the central portion of the duct I6| and permits oil to flow from the rear end of the duct |6| to the front end. The lower end of the vertical longitudinally extending passage |63 communicates with the annular groove |62. The cross port |64 establishes communication between the upper end of the passage |63 and the annular groove |65 in the bottom part |48 of the slide block |41. The ports |66 lead outwards from the annular groove |65 and open onto the inner faces of the side pieces oi' the frame |50. When oil underpressure is supplied by the gear pump 96 to the interiors of the members 11 and 18 a portion of such oil ows through the duct |6|, then into the annular groove |62, then upwards through the passage |63, then into the annular groove |65 via the cross port |64 and from the annular groove through the ports |66 onto the inner faces of the side pieces of the frame |50. By lubricating such side faces the slide block |41 slides freely in the frame in connection with reciprocation of the toolcarrying plunger I5. Any excess oil which builds up on the inner faces of the side pieces of the frame flows downwards through the longitudinal slot |54 onto the upper central portion of the plunger I5 and serves to lubricate such plunger. The oil which nows onto the upper central portion of the plunger flows around the central portion of the cylinder 16 and flows into the chamber 46 via a hole |61 in the lower portion of the upper housing section 43. The front end of the cylinder 16, that is, the end that is nearer the electric motor |3, is provided with a pair of spaced apart ring shaped oil grooves |68. These grooves are cross connected by a longitudinally extending grove |69. 'I'he upper portion of the inner annular groove |68 communicates with the front end of the slot |54 by way of a longitudinal .groove |10. The central portion of the plunger is provided with an annular exterior groove |1| and this communicates with the slot |54 and serves to supply oil from the slot to the central portion of the cylinder. The front end of the cylinder is lubricated by way of a longitudinal duct |12 which, as shown in Figure 4, leads from the inner end of the interior of the tubular member 11 to that portion of the front end of the cylinder which is between the annular grooves |68. Any excess oil that is sup plied to the front end of the cylinder by the duct is delivered to the slot |54 by way of the groves |68, |69 and |10. 'I'he front end of the inner face of the guide bar |51. is lubricated by way of a horizontal passage |13 in the block 88. One end of this passage communicates with the front end of the longitudinal duct |6| in the plunger |5 and the other end of the passage extends through the extension |60 and opens onto the front end of the inner face of the guide bar.

When oil'under pressure is supplied by the gear pump 96 to force the plunger |5 towards the electric motor for plug cutting purposes the portion of the oil that nows into the front end of the duct |6| flows through the passage |13 in the tool carrying block 88 and serves to lubricate the Vface portions of the extension |60 and the guide bar |51 that are in sliding engagement.

Automatic control means for motor, centering pin and plunger Figure 1l of the drawings shows in a diagrammatic manner the various automatic control means for the operating parts of the lathe. Such means include a three-phase currentsupply |14, a multiple switch mechanism |15, a limit switch |16 and a starter switch |11. The three-phase current supply |14 consists of three lines |18, |16 and |80. The multiple switch mechanism |15 is of the normally open variety and embodies four switches |8|, |82, |83 and |84. The switch |8| consists of a pair of spaced apart contacts |8| and |8|b and a. bridge member |8|. The contact |8|a is connected to the line |18 and the contact |8|bis connected to the stator of the electric motor I3 by a conductor |85. The switch |82 consists of a pair of spaced apart contacts |82*L and |82b anda bridge member |82. The contact |82 is connected to the line |19 and the contact |82b is connected by a conductor |86 to the stator of the electric motor |3. The switch |83 consists of a pair of spaced apart contacts |83 and |83h and a bridge member |839 The contact |83a is connected to the line |80 and the contact |83b is connected by a conductor |81 to the stator of the electric motor I3. The switch |84 is for a hereinafter described holding circuit and consists of a pair of spaced apart contacts |842 and |84b and a bridge member |84. The bridge members of the four switches 18|, |82, |83 and |84 are mounted on an insulated slide rod |88 and are adapted when the rod is shifted in one direction to effect closing of all four switches and when the rod is shifted in the opposite direction to open the four switches. A tension spring |89 is applied to one end of the slide rod |88 and serves to urge the rod into a position wherein the four bridge members 18|, |82c, |83e and |84c are out of bridging relation with their respective contacts. A solenoid |90 serves when energized to shift the rod |88 into a position wherein the four bridge members effect closing of the four switches |8|, |82, |83 and |84. This solenoid comprises a coil |9| and an armature |92. The armature is applied to the other end of the rod |88. When the solenoid |90 is energized it effects closing of the four switches constituting parts of the multiple switch 4mechanism |15. When the switches |8|, |82 and |83 are closed the 3-phase circuit for the electric motor I3 is established with the result that'the motor is set in operation. The limit switch |16 is a normally closed switch and is located on the front end of the upper housing section. It comprises a pair of spaced apart contacts |16a and |16b and a movably mounted bridge member |166. The bridge member is urged into contact or bridging relation with the two contacts |16 and |16b by a tension spring |16d. It is provided with a button |16e which projects rearwards and is aligned with a iinger |93 on the top part |49 of the slide block |41. This finger, as shown in Figure '7, underlies and is disposed in parallel relation with the control rod |45 for the retarding valve ||2 and is so arranged that when the tool carrying plung..

, of the switch |83.

I contactne and 2,889,904 er I reaches the lend of its cutting stroke it moves into engagement with the button |16'l and forces the bridge member I16 into its open position against the force of the compression spring |169. One end of the coil |9I of the solenoid |90 is connected to the contact |8Ia of the switch I8I by a. conductor |94. The other end of the coil |92 is connected by a conductor |95 to the contact |169 of the limit switch |16. The starter switch |11. is mounted on the housing 4I and is of the 2-pole double throw variety. It comprises a pair of spaced apart contacts |11 and |119, an opposed pair of spaced apart contacts |11c and |119 and a movably mounted bridge member |119.

The bridge member |11e is operatively connected to the central portion of a lever |11f. One end of this lever is hinged or pivoted and the other end is'in the form of a handle. A compression spring '|115 is applied to the lever |11t so that it is urged outwards into a position wherein it maintains the bridge member |11e in engagement or bridging relation with the contacts |11c and |119. When the lever is shifted inwards the bridge member |11e is shifted out of bridging relation with the contacts |11c and |119 into ycon tact or bridging relation with the contacts |11"l is opened by the finger |93 with the result that the circuit for the solenoid |90 is broken and the switches |8I, I82, |83 and |84 are opened by the action of the tension spring |89. Opening of the switches |8I, |82 and |83 results vin stoppage of the electric motor I3. Return of the limit switch |16 in connection with 'retraction of the plunger I5 does not result in the solenoid |90 again being energized because once the solenoid is de-energized asv the result of opening of the limit switch the holding circuit consisting of the conductor |98, switch |84 and conductor |99 is broken. If desired a normally closed emergency stop switch ductor |96 and makes it possible to stop the lathe at any time. The contact |119 of the starter yswitch |11 is connected to the line |80 by a conductor 20|. The contact |119 of the starter switch' is connected to one end of the coil |28 of the solenoid valve member ||4 by way of a conductor 202. The other end of the coil |29 is connected to a terminal 203. A conductor 204 fis connected to the conductor 202 and leads to and |119. A compression spring |11h is located adjacent the handle of the lever and serves so to retard inward shift of the lever as to produce a lag or delay in connection with shift of the bridge member I119-into bridging relation with the contacts |119 and |119. The contact |16b of the limit switch |16 is connected to the contact |11a of the starter switch 11 by a conductor |96. The contact |11b of the starter switch is connected to the contact |849 of the switch |84 by a conductor |91. The other contact of the switch |84, i. e., the contact |849, is connected by a conductor |98 to the conductor |96 between the contacts |169 and |119. A conductor |99 extends between and, serves to connect the contact |849 of the switch |84 and the contactk |83n When the lever |11t is shifted inwards in connection with starting of the lathe it causes the bridge member |11e to bridge the contacts |11B and |11". As soon as these two contacts are bridged the solenoid |90 is energized as the result of the establishment of the following circuit: line |18, conductor |94, coil I9|, conductor |95, normally closed limit switch |16, conductor I 96, conductor |91, conductor I 89 and line |80. As soon as the solenoid |90 is energized it shifts the rod] |88 so as to close the switches |8I, |82, |83 and |84. As'vsoon as the switches I8|, |82 and" |83 are closedthe electric motorV I3 is set into operation as the result of the 3-phase motor circuit. The conductor |98 and the switch |84 constitute a holding circuit formaintaining the solenoid |90 energized after the lever I11f 'is released and while the limit switch |16 is in its closed position. As soon as the lever |11f is released the spring I1.1 urges it outwards and results in the bridge member |11 moving out of bridging relation with the |11b into bridging relation with the contacts |11 and I 119. When the bridge member I11 is out of bridging relation with the contacts |119 and |11b as the result of release of the lever |111, the solenoid |90 remains ener-v gized'jbecause of the holding circuit which is established between the conductor |98 and tle line |80, such holding circuit consisting of the conductor |98, the switch |84 and the conductor |99. When the tool carrying plunger I6 reaches the end of its cutting strol e the limit switch |18 40 motor for plug cutting purposes.

closes and completes y is released after I.|119 and and is connected to one end of the coil 68 of the solenoid partv of the solenoid valve 62. The other 'end of the coil 68 is connected to the terminal 203 by a conductor 205. 'A conductor 208 extends between and connects the terminal 208 and the line |19. When the lever' |11 of the starter switch |11 is shifted forwards to effect starting of the lathe the bridge member |11e is shifted out of bridging relation with the contacts |11c and |119. This serves to break the circuits for the solenoid partsl of the valves 62 and II4 with the result that such valves close. As hereinbefore described, closing of the valve 62 results in forward shift of the centering pin |4 and closure of the valve |I4 results in the tool carrying plunger I5 being shifted toward the electric The plunger inward shift the 3-phase is shifted toward the motor because of the lever I11f eiects closing of circuit for the motor I3 and/the motor operates I to drive the gear pump 96. When the lever |11t starting of the lathe the contacts |119 are bridged by the bridge member I11.. In order to prevent such bridging of the contacts |119 and |119 from energizing thesolenoid parts of f the solenoid valves 62 and II4 while the motor I3 is in operation a switch 201 and a solenoid 208 are provided. The switch 201 is included in the conductor 206. It is of the'normally closed type and comprises a pair of contacts 2019 and 201b and a bridge member 201. The bridge member 201c is normally held in engagement or bridging relation with the two contacts 2019 and 201h by a tension spring 2019. The solenoid 209 serves to hold the switch 201 in its Yopen position during operation of the electric motor I3. It comprises a coil 209 and an armature 2 I0. One end'of the coil 2|0 is connected by a conductor 2|| to the conductor |86. The other end of the coil 2|0 is connected by a conductor 2|2 to the conductor |86. When current is supplied to the motor I3 as the result of closure of the 3-phase motor circuit the solenoid 209 is energized and the amature 2|0 operates to open the switch 201. As soon as the motor I3 stops as the result of opening of the limit switch |16 at the' end of the cutting stroke` of the tool carrying plunger I5 the solenoid 208 is de-energized with the result that the switch 201 the circuits for the solenoid parts of the solenoid valves 62 and I I 4.

'rue solenoid u o: tno solenoid typo' broke a1 u zoo is included m the con- ,i

supplied with current by way of a pair of conductors 2|3 and 2|4. The conductor 2|3 is connected to the conductor |85 and the conductor 2|4 is connected to the conductor |86. When current is supplied to the motor I3 the solenoid 38 of the solenoid type brake 31 is energized and operates to release the brake shoe 38. Stoppage of current to the motor |3 results in the solenoid 38 being de-energized with the resultant application of the brake shoe 38 to the outer end of the armature shaft 28 of the motor I3.

Operation Assuming that the B-phase current supply |14 is ln connected relation with a current source the operation of the lathe is as follows:

As a preliminary step the lathe .operator manipulates the plug p so as to bring the polygonal lug at the large end thereof into the slot 35 in the chuck 34. After this manipulation the operator releases the plug with the result that the plug drops downwards until the reduced externally threaded nut receiving stem at its small end comes in seated relation with the notch defining portion 'of the upstanding plate 14 on the depending member 13 of the bracket 12. After the plug is in place the operator shifts inwards the lever |11t of the starter switch |11. During the initial portion of the inward shift of the lever the bridge member |11e is shifted out of engagement or bridging relation with the contacts |'|1c and |11d. This results in stoppage of current through the circuits for the solenoid parts of the solenoid valves 62 and |I4. As soon as such circuits are broken the two valves automatically close as hereinbefore described. Closing of the solenoid valve 62 results in air under pressure building up within the upper portion of the chamber 45 and causing the oil in the lower portion of the chamber to iiow into the socket 48 via the duct 56. The oil that enters the socket forces the centering pin I4 towards the electric motor and results in the point 53 on the front end of the centering pin entering the tapered or conical socket in the externally threaded reduced stem of the small end of the plug p. As the point 53 entersy such socket it cams the small end of the plug upwards and also laterally in the direction of the cutting tool. This serves properly to position the plug p for cutting. During the initial part of the inward shift of the lever I11f of the starter switch |11 the solenoid valve |I4 closes, as hereinbefore pointed out. Closing of the valve does not, however, result in sliding movement of the plunger towards the motor because at the time that the valve is closed the gear pump 86 is not in operation. When the lever |11f of the starter switch |11 is shifted further inwards against the force of the compression `spring |11h it causes the bridge member |11e to bridge the contacts |11 and |11. Bridging of these two contacts by the bridge member |11e results in release of the solenoid brake 31 and starting of the motor 3. As soon as the motor starts it operates to drive the chuck 34 for plug rotating purposes and also sets the pump 86 in operation. The pump immediately upon starting thereof draws oil from the chamber 46 via the branch pipe I I8 and the pipe section |88 and forces the oil under pressure into theinteriorsof the members 11 and 18 via the pipe |82. Because the solenoid valve I I4 is closed the oil that is introduced into the interiors of the members 11 and 18 builds up pressure and forces the plunger towards the motor. It is contemplated 62 and ||4 because as soon as the electric motor- |3 starts the solenoid 208 is energized and operates, as hereinbefore described, to open the normally closed switch 281 in the conductor 288. During sliding movement of the plunger l5 towards the motor the cutting edge 83 of the tool traverses the sidesurface of the cock plug p and serves to provide the plug with the desired truly tapered or conical exterior side surface. As the plunger approaches the end of its cutting stroke the slide block; |41 moves into engagement with the enlarged head |46 at the front end of the rod |45 and shifts the spool type valve member |26 on the retarding valve ||2 into its closed position. At the end of the cutting stroke of the plunger the finger |83 opens the limit switch |16, as hereinbefore described. Opening of the limit switch |16 causes the circuit for the solenoid |88 to be broken. Interruption of the ilow of current through the circuit for the solenoid |88 results in opening of the switches |8|, |82, |83 and |84., As soon as these four switches are opened the electric motor |3 stops and the solenoid 288 becomes de-energized. As soon as the last mentioned solenoid becomes de-energized the switch 281 closes with the result that the solenoid parts of the solenoid valves 62 and I|4 are energized and result in opening of such valves. As soon as the valve 62 opens air under pressure in the upper portion of the chamber 45 is released and the compression spring 54 operates to retract the centering pin I4. The centering pin retracts before there isV any appreciable retraction of the plunger I5 because of the action of the retarding valve |I2. Retraction of the centering pin results in the small end of the cut or surfaced plug shifting downwards and away from the cutting tool into a position wherein the plug is out of cutting relation or contact with the cutting edge of the tool 8|. Opening of the solenoid valve 62, in addition to resulting in retraction of the centering pin |4, also results in the nozzle 1I directing a jet of air downwards against the point of the retracted centering pin so as to clear such point of any cuttings or other foreign particles which would preclude 'it from functioning properly in connection with the subsequent operation of the lathe. The initial part of the retractile stroke of the plunger is extremely slo`w because of the closed position of the spool type valve member |26. When the plunger is retracted sufficiently by the spring 85 to resultfin opening of the spool type valve member |26 by the spring i8! the retarding valve ||2 opens and the oil in the interiors of the members 11 and 18 is released so that it flows back into the chamber 46 via the pipe section |86, the casing ||1 of the solenoid valve I'I4, the pipe section |81 and the branch pipe ||8. As soon as there is a free flow of oil from the interiors of the members 11 and 18 the compression spring 85 effectsquick and complete retraction of the plunger I5. When the plunger is in its fully retracted position the cut or surfaced plug p is removed from the chuck 38 and the upstanding plate 14, and the lathe is in readiness for another cutting operation. If it is deascaeoa loosened and the bed plate 2| together with the motor .I3 is'shifted away from the bracket 3|. Such adjustment results in the centering pin 36 of the chuck 34 being shifted laterally with respect to the point on the front end of the centering pin I4. If it is desired to decrease the amount of taper ofl the side surface of the plug p the motor I3 is adjusted towardsthe bracket 3|.

The herein described lathe is essentially simiple in design and is characterized by high speed of operation and efliciency. It is in the form of a compact unit and is capable of being produced and operated at an extremely low cost. Because the lathe includes automatic means for lubricat' ing the plunger and cylinder and the parts that are associated therewith the lathe as a whole has exceptionally long life. u

'Whereas the lathe has been described Aas being primarily designed for use in providing acock u plug with a tapered external side surface it is to other end ,of the work piece and'away from the chuck into a work piece releasing position, a cylinder on .the supporting structure disposed at one vside of, and substantially in parallel relation with, the centering pin and having the end thereof nearer the motor open and its other end closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting tool, and adapted when slid l outwards'in the direction 0f the chuck to have the tool traverse the' work piece and effect cutting thereof, switch controlledmeans for supplying electric current to the motor, a gear pump connected for drive by the motor and operative 15 when driven to deliver liquid under pressure into the cylinder and .cause the plunger to slide t0- wards the motor, means for automatically 'interrupting the ow of electric current to the motor when the plunger reaches the' end of its cutting,l

stroke, means for automatically ventingvthe 'cyl-V inder when said plunger reaches the end of its cutting stroke, and spring means for retracting be understood that it may be used in other capacities,"that is, in surfacing other'parts or articles. It is also to be understood that the inven-v tion is not to be restricted to the details set forth since these may be modified Within the scope of the appendedclaims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. A lathe designed to cut the surface of a work piece and comprising a Supporting structure, an electric motor mounted on said structure, a chuck connected for drive by the motor land adapted to support one end of and to drive the work piece, a centering pin positioned in opposed relation .with the chuck and mounted on the supporting structure so that it is movable towards the chuck into a position wherein it serves to support 'the other end of the work piece and away from the chuck into a work piece releasing position, a cylluder-on the supporting structure disposed at one side of, and substantially in parallel relation with, the centering pin and having the end thereof nearer the motor open and its other end closed,

- a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting, tool, and adapted when Vslid 'outwards in the direction of the chuck to vhave thetool traverse the work piece andeffect cutting thereof, switch controlled means for supplying electric current to the motor, a rotary pump connected for drive by'the motor and operative when driven to deliver fluid under pressure into the cylinder to cause the plunger to slide towards'the motor, means for automatically interrupting the flow of electric current to the motor when the plunger reaches the end of its cutting stroke, me'ans for automatically venting the `cylinder when said plunger reaches the end 0f its cutting stroke, and means for retracting the plunger upon stoppage of the motor and venting of the cylinder.

2. A lathe designed to cut the surface of a work piece and comprising ya supporting struc.`

ture, an electric motor mounted on said structure and provided on one end of the armature shaft thereof with aA chuck adapted to support.

one end of the work piece and also to drive said work piece in response to operation of the motor,

a centering pin positioned in opposed relation with the chuck and mounted on the supporting structure so that it is movable towards the chuck into a position wherein it serves to support the 'the work piece, a centering pin positioned in opposed relation with the chuck and mounted on 4the supporting structure so that it is movableto- Iwards the chuck into a position wherein it serves to supportl the other end of the work piece and away from the chuck into' a work piece releasing position, a cylinder on the supportingstructure disposed at one side of, and substantially in parallel relation with, the centering pin and having the end thereof nearer the motor open and its 4|) other lend closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided With a cutting tool, and adapted when slid outwards in the direction of the chuck to have the tool traverse the work piece and effect cutting thereof, switch controlled means for supplying current to the motor, a pump connectedv for drive by the motor and operative when driven to` deliver fluid under pressure into the cylinder j toA cause the plunger to slide towards the motor, means for automatically interrupting the flow of current to the motor when the plunger reaches the end of its cutting stroke, means for automatically venting the cylinder when said plunger reachesl the end of its cutting stroke, means for retracting the plunger upon stoppage of the motor and venting ofthe cylinder, means operative automatically upon closing of the switch to move the centering pin into its work piece supporting position, and means for shifting the centering pin into its work piece releasing position upon stoppage of the motor..

4. A lathe designed to cut the surface of a work piece and comprising a supporting struc- ,ture, an electric motor mounted on said structure and provided lon one end of the armature shaft thereof with a chuck adapted to support one end of the work piece and also to drive said work piece in response to operation of said motor, a centering pin positionedin opposed relation with the chuck and mounted on the supporting structure so that it is movable towards the chuck int)` a position wherein it serves to sufpport the other end of the -Work Ipiece and away from the chuck into a work piece releasing position, acylinder on the supporting structure disto have the tool traverse the work piece and effeet cutting thereof, switch controlled means for supplying electric current to the motor, a pump connected for drive by the motor and operative when driven to deliver uid under pressure to the cylinder to cause the plunger to slide towards the chuck, means, for automatically interrupting the 'ow of electric current to the motor when the plunger reaches the end of its cutting stroke,

means for automatically venting the cylinder when said plunger reaches the end of its .cut-

ting stro-ke, and a compression spring in the cylinder for retracting the plunger upon venting of said cylinder.

- 5. A lathe designed to cut a tapered surface on a work piece and comprising a supporting structure, an electric motor positioned over the structure and provided on one end of the armature shaft thereof with a chuck adapted to support one end of the work piece and also to drive said work piece in response to operation of the motor, a centering pin .disposed in opposed relation ,with the chuck and mounted on the supporting structure so that it is slidabletowards the chuck into a position wherein it serves to support the other end of the Work piece andaway from the chuck into a work piece vreleasing position, a

cylinder on the supporting structure disposed at one side of, and extending at a small acute angle with respect to, the centering pin, and having the end thereof nearer the chuck open and its other end closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting tool, and adapted when slid outwards-in the direction of the chuck to have the tool traverse the work piece to effect cutting thereof, a pump connected for drive by the motor and operative'when driven to deliver fluid under pressure into the cylinder to cause the plunger to slide towards the chuck, and a common mount for the motor and pump slidably mounted on the supporting structure so as to permit the motor to be adjusted laterally.

6. An' apparatus'designed to cut a work piece and comprising a supporting structure embodying a tubular, horizontally extending, open ended frame member and a channel beam positioned above, and extending lengthwise of, the top portion of the frame member and having the side ilanges thereof extending downwards towards, and connected to, said top portion of said frame member, a power driven chuck positioned over one end of the channel beam and adapted to support one end of and drive the work piece, a centering pin positioned over the other end of the channel beam and in opposed relation with the chuck rand mounted so that it is -shiftable towards the chuck into a position wherein it serves to support the other end of the chuck and away from the chuck into a work piece releasing position, means atione side of the centering p-in for supporting a cutting tool so that it serves to out the work piece, andan open bottom hopper beneath the chuck and centering pin adapted to receive the cuttings caused by the tool and hav ing the lower end thereof extending through aligned openings in the web of the channel beam and the upper portion or the frame member and l i l adapted to direct the cuttings into the interior of said frame member.

7. A lathe designed to cut a 'work piece and comprising a supporting structure embodying a tubular, horizontally extending, open ended frame member and a channel beam disposed above, and extending lengthwise of, the lupper portion of the frame member and having the side flanges thereof extending downwards towards, and connected to, said upper portion of the frame member and serving to space the web of the beam from said upper portion of the frame member so as to form a space therebetween, a power driven chuck positioned over one end of the beam and adapted to support one end of the work piece and also to drive said work piece, a centering pin positioned over the other end of the channel beam and in opposed relation with the c huck and mounted so that it is movable towards the chuck into a position wherein it serves to support the other end of the work piece and away from the chuck int'o a work piece releasing position, a cylinder disposed at one side of, and in substantially lparallel relation with, the centering pin and having the end thereof nearer the chuck open and its other end closed, a plunger having one end thereof slidably mounted inthe cylinder andits other end provided with a cutting4 tool, and adapted when slid outwards in the direction of the chuck to have the tool traverse the work piece and effect cutting thereof,and means for supplying liquid under pressure into the cylinder in ordel` to cause the plunger to slide towards the chuck, embodying a power driven pump adjacent said one end of the channel beam and a pipe extending through said space and having one end thereof connected to the pump and its other end in 'communication with the cylinder.

8. A lathe designed to cut a work piece and comprising a supporting structure embodying a tubular, horizontally extending, open ended' frame member and a channel beam disposed'above, and extending lengthwise of, the upper portion of the frame member and having the side iianges thereof extending'downwards towards, and connected to, said upper portion of the frame member and serving to space the web ofv the beam from said upper portion of the frame member so as to form a space therebetween, a power driven chuck positioned over one end of the beam and adapted to support one end of the work piece and also to drive said work piece, a centering pin positioned over the other end of the channelv beam and in opposed relation with the chuck and mounted so that it is movable towards the chuck into a position wherein it serves to support the other end of the work piece and away from the chuck into a work piece releasing position, a cylinder disposed at one side of, and in substantially parallel relation withy the centering pin and having the end thereof nearer the chuck open and its other end closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting tool, and adapted when slid outwards in the direction of the chuck to have the tool traverse the work piece and effect cut-l ting thereof, means for supplying liquid under pressure into the cylinder in order to cause the plunger to slide towards the chuck, embodying a power driven pump adjacent said one end of the channel beam, and a pipe extending through said space and having one end thereof connected to the pump and its other end in communication beneath the chuck and centering pin adapted to catch the cuttings caused by the tool and having the lower end thereofr extendingl through aligned openings in the web of the channel beam and the upper portion of the frame member and adapted to direct such cuttings into the interior of the frame member. l

9. An apparatus designed to cut a work piece and comprising a 'supporting structure, a ,power driven chuck positioned over the structure and adapted to supportone end of and drive the work piece, a housing mounted on the supporting struc.- ture in opposed relation with the chuck and having in substantial alignment -with the chuck a cylindrical type socket with the end thereof nearer the chuck open and its other end closed, a centering pin slidably mounted in the socket and adapted when slid outwards to engage and support the other end of the workpiece, means forming a closed chamber for a limited quantity of liquid, means establishing communication between the inner end of the socket and the bottom of the chamber, means for delivering a gas under pressure into the upper portion of the chamber in order to cause the liquid to iow from the chamber into the socket and cause the centering pin to move outwards into its work piece supporting position, valve controlled meansfor venting said upper portion of the chamber, means for automatically retracting the centering pin upon venting of said upper portion of said chamber, and means at one side of the centering pin for supporting a cutting tool so that it serves to cut the work piece when the latter is supported by the chuck and centering pin. i

10. An apparatus designed to cut a work piece and comprising a supporting structure, a power driven chuck positioned over the structure and adapted to support one end of and drive the work piece, a housing mounted on the supporting structure in opposed relation with the chuck and having a cylinder type socket in substantial align ment with the chuck .and the one end thereof nearer the chuck open and its other end closed,

and also having beneath the socket a closed chamber and with a partial lling of liquid therein, and a duct extending and establishing ccmmunication between the bottom of the chamber and the inner end of the socket, means for delivering a gas under pressure into the upper por4 tion ofthe chamber in order to cause'the liquid to now from the chamber into the socket and force the centering pin to slide outwards into its work piece supporting position, valve controlled means for venting said upper portion of thechamber, spring means for retracting the centering pin upon venting of said upper portion of the chamber, and means at one side of the centering pin for supporting a cutting tool so that it serves to cut the work piece when the latter is supported by the chuck and centering pin.

l1. An apparatus designed t'o cut a work piece and comprising a supporting stru-cturea powery a centering pin slidably mounted in the socket and adapted when slid outwards to engage and support the other end of the work piece, means forming a closed chamber for a limited quantity of liquid, means establishing communication between the bottom of thechamber and the inner end of the socket, a pipe connected to a source of air under pressure, having one end thereof in communication with the upper portion of the chamber, vprovided at its other end with a valve having the outlet thereof leading to atmosphere, andadapted when the valve is closed to supply air under pressure into the upper portion of the chamber in order to cause the liquid in the chamber to ow into the socket and cause the centering pin to slide outwards into its work piece supporting position, and further adapted when the valve is opened to vent the upper portion of the chamber and permit back'ow of the liquid from the socket into the chamber, means for retracting the centering pin upon back flow of the liquid from the socket into the chamber as'the result of opening of the valve, and means at one side of the centering pin for supporting a cutting tool so that it serves to cut the work piece when the latteris supported vby the chuck and centering pin.

12. An apparatus designed to out a work piece and comprising a supporting structure, a power driven chuck positioned over the structure and adapted to support one end of and rotate the work piece, a housing mounted on the supporting structure in opposed relation with the chuck, and having a cylindrical socket in substantial alignment with the chuck and with the end thereof nearer the chuck open and its other end closed, a centering pin slidably mounted in the socket and adapted when slid outwards to engage and support the other end of the work piece, a spring in the inner end of the socket for urging the centering pin inwards out of its work piece supporting position,

i means forming a closed chamber for a limited quantity of liquid, means establishing communil flow from the chamber into'the socket and cause it to force the centering pin outwards into its work piece supporting position against the force of the spring, and further adapted when the valve is opened to vent said upper portion of the chamber so as to permit back ow of the liquid from the socket to the chamber and retraction of the centering pin by' the spring, and means at one side of the centering pin for supporting a cutting tool so that it serves to cut the work piece when the latter is supported by the chuck and center ing pin. f f 'f 13. An apparatus designed to cut a work piece and comprising a supporting structure, a power driven chuck` positioned over the structure and adapted to support one end of and rotate the work piece, a housing mounted on the supportingl structure in opposed relation with the chuck and having a cylinder type socket in substantiaI alignrnent with the chuck and with the end thereof nearer the chuck open and its other end closed, a centering pin slidably mounted in' the socket and adaptedvhen slid outwards to engage and support the other end Rof the work/piece, means beneath the socket forming msed chamber for a limited quantity of liquid, megns establishing communication between the bottom of the chamber and the inner end of the socket. a pipe connected to a source of air under pressure, having one end thereof in communicationwith the upper portion of the chamber, adapted when the valve is closed 2o supply air under pressure into the upper portion of the chamber in order to cause the liquid in the chamber to now into the socket and cause the centering pin to slide outwards into its work piece supporting position, and further adapted when the valve is opened to vent the upper portion of the chamber and permit back flow of the liquid from the socket into the chamber, means for retracting the centering pin upon back iiow of the liquid from the socket into the chamber as the result of opening of the valve, a pipe having one end thereof connected to the outlet of the valve and its other end arranged so that it faces the outer end of the centering pin when the latter is in its retracted position and adapted when the valve is opened to deliver the air under pressure emanating therefrom against said outer end of the centering pin, and means at one side of the centering pin for supporting a cutting tool so that it serves to cut the work piece when the latter is supported by the chuck and centering pin.

14. A lathe designed to cut the surface of a work piece and comprising a supporting structure, a power driven chuck positioned over the structure and adapted to support one end of and drive the work piece, a housing mounted on the supporting structure in opposed relation with the chuck and having a cylinder type socket in substantial alignment with the chuck and with the end thereof nearer the chuck open and its other end closed, a centering pin slidably mounted in the socket and adapted when slid outwards to engage and support the other end of the work piece, means forming a closed chamber for a limited quantity of liquid, means establishing communication between the bottom of the chamber and the inner end of the socket, means for delivering a gas under pressure into the upper portion of the chamber in order to cause the liquid to flow from the chamber into the socket and force the centering pin to move outwards into its work piece supporting position, means including a valve for venting said upper portion of the chamber, means for retracting the centering pin upon opening of the valve, an element at one side of the centering pin mounted to slide rectilinearly to and from the chuck, provided with a cutting tool, and adapted when slid towards the chuck to have the tool traverse the work piece and effect cutting thereof, and means for automatically opening the valve when the element reaches the end of its cutting stroke.

l 15. A lathe designed to'cut the surface of a work piece and comprising a supporting structure, a power driven chuck positioned over the structure and adapted tosupport one end of and rotate the work piece, a housing mounted on the supporting structure vin opposed relation with the chuck and' having a cylindrical socket in substantial alignment with the chuck and with the end thereof nearer the chuck open and its other end closed, a centering pin slidably mounted in the socket and adaptedwhen slid outwards to engage and support the other end of the work piece, a spring in the inner end of the socket for urging the centering pin inwards out of its work piece supporting position, means beneath the socketforming a closed chamber for a limited quantity of liquid, means establishing communiaseaeoc cation between the bottom of the chamber and the inner end of the socket, a pipe connected to a source of air under pressure, having one end thereof communicating with the upper portion of the chamber, provided at its other end with a valve having the outlet end thereof leading to atmosphere, adapted when the valve is closed to deliver air under pressure into the upper portion of the chamber in order to cause the liquid to flow from the chamber into the socket and force the centering rpin outwards into its work piece supporting position against the force of the spring, and further adapted when the valve is opened to vent said upper portion of the chamber so as to permit back flow of the liquid from the socket to the chamber and retraction of the centeringpin 'by the spring, a cylinder disposed at one side of, and in substantially parallel relation with, the centering pin and having the end thereof nearer the chuck open and its other end closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting tool, and adapted when slid outwards in the direction of the chuck to have the tool traverse the work piece and eifect cutting thereof, means for supply fluid under pressure into the cylinder to cause the plunger to slide towards the chuck, means including a. valve for venting the cylinder, means for retracting the plunger upon venting of the cylinder, and means for automatically and simultaneously opening the two valves when the plunger reaches the end of its cutting stroke.

16. A lathe designed to cut the surface of a work piece and comprising a supporting structure, a power driven chuck positioned over the structure and adapted to support one end of and drive the work piece, a housing mounted on the supporting structure in opposed relation with the chuck and having in substantial alignment with the chuck a cylinder type socket with the end thereof nearer the chuck open and its other end closed,- a centering pin slidably mounted in the socket and adapted when slid outwards to engage and support the other end of the work piece, means beneath the socket forming a cio-sed chamber for a limited quantity of liquid, means establishing communication between the inner end of the socket and the bottom of the chamber, means for delivering a gas under pressure into the upper portion of the chamber in order to cause the liquid to flow from the chamber into the socket and cause the centering pin to move outwards into its work piece supporting position, means including a normally closed solenoid valve for venting said upper portionof the chamber, means for retracting the centering pin upon opening of the valve and resultant venting of the upper portion of said chamber, a cylinder disposed at one side of, and in substantially parallel relation with, the centering pin and having the end thereof nearer the chuck open and its other end closed, a plunger having one end thereof slidably mounted in the cylinder and its other end provided with a cutting tool, and adapted when slid outwards in the direction of the chuck to have the tool traverse the work piece and effect cutting thereof, means for supplying fluid underpressure into the cylinder to cause the plunger to slide towards the chuck, means including a normally closed solenoid valve for venting the cylinder, means for reti-acting the plunger upon opening of the last mentioned valve and resultant venting of the cylinder, and means for supplying current to the two valves when the 

